The motion controllers can be used in blueprint just like normal ones, the difference between mine and the engine ones are that they replicate over the network by themselves and they have a bunch of built in grip functions. You don’t have to use the grip functions if you don’t want to but they offer additional features over what is possible in blueprint. I wouldn’t attach additional controllers on construction, I would just use the ones already attached to the character and modify scripts that you are using for them. I realize that epic uses seperate blueprints for thiers and handles the pickup functionality within those but since the grip functions are built into my controllers I just add overlap spheres or run traces directly from within the character itself.
Scripts need to reference GripMotionControllers instead of MotionControllers as I was unable to get all of the features in just deriving from the standard motion controllers and ended up having to re implement them entirely.
Interfacing with the GripMotionControllers is all done with blueprint though, the plugin isn’t intended to be used with code only (although it is possible).
You can feel free to set the default controllers to not Tick and hide them and use epics blueprint versions if you wish though, it doesn’t hurt anything. I will mention that the built in functions support world interacting grips and two handed interaction with objects and that may save you some time depending on what your plans are.